1. Field of the Invention
The invention relates to an air-suspension system having at least one air spring for installation between a chassis and a vehicle component mounted for oscillating along an oscillatory path relative to the chassis, the air spring having a control valve for feeding, blocking, or discharging compressed air in the air spring.
2. Description of the Related Art
An air suspension system is disclosed, for example, in German reference DE 33 47 435 A1 having an air spring connectable between a chassis of a vehicle and a vehicle component mounted for oscillating along an oscillation path relative to the chassis. A control valve is arranged for feeding, blocking, or discharging compressed air in the air spring. A basic problem with the disclosed system is that it is difficult to fit and adjust the control valve or a actuating device for the control valve so that a certain switching position of the control valve is set as a function of a loading state or a stroke position of the air spring.
Additional construction space and fitting material (i.e., holders, linkages, screws, etc.) are required for fitting the external level control valve.
During the fitting of the control valve, the vehicle component mounted for oscillating is put into a defined position relative to the chassis and an adjustment of the actuating device is made in this position. However, this sequence of work is difficult to integrate in an assembly line production.
Furthermore, the operability of the external level control valve and thus of the vehicle may be impaired by dirt or moisture when using an air-sprung vehicle in difficult terrain.
Another air-suspension system for a motor vehicle is disclosed in German reference DE 34 27 902 A1 having at least one air spring between a chassis and a vehicle component mounted for oscillating along an oscillatory path relative to the chassis. This reference also has a control valve for feeding and discharging compressed air inside the air spring, wherein the control valve is activated via an actuating device which is likewise arranged inside the air spring.
Yet another air-suspension system for a motor vehicle is disclosed in German reference DE 44 09 252 C2 with at least one air spring arranged between a chassis and a vehicle component mounted for oscillating movement along an oscillatory path relative to the chassis and a control valve arranged inside the air spring. The control valve has control positions for feeding, blocking and discharging compressed air and is activated via a control element which is likewise arranged inside the air spring. A guideway of the control valve acts on one of the two air-spring subassemblies of the outer tube and the rolling tube which are movable relative to one another. This control valve is designed as a rotary-slide valve activated via the guideway and a rotary-slide valve body. In the embodiment according to FIGS. 6 and 7 of this reference, the control element is firmly connected to the outer tube. The result of this control element arrangement is that the entire length of the control element has to be accommodated inside the air spring. Consequently, the rolling tube must be arranged relatively close to the base of the vibration damper which restricts the heat exchange between the vibration damper and the surroundings.